The California aqueduct (444 miles, 714km) would like to have a word :-).
Basically built for the same reason, the central valley of California was mostly arid but the top soil was good for agriculture. The underground aquifer was a limit on how much farming (and of what type) could be done.
Basically built for the same reason, the central valley of California was mostly arid but the top soil was good for agriculture. The underground aquifer was a limit on how much farming (and of what type) could be done.